CALLING MATLAB FROM C

I wanted to call a Matlab code from C program. However, when I try
the example given in help, I met the following errors. Can sb tell me

what's wrong?
Thank you very much!
 
engwindemo.obj .text: undefined reference to '_engOpen'
engwindemo.obj .text: undefined reference to '_engPutArray'
engwindemo.obj .text: undefined reference to '_engEvalString'
engwindemo.obj .text: undefined reference to '_engOutputBuffer'
engwindemo.obj .text: undefined reference to '_engGetArray'
engwindemo.obj .text: undefined reference to '_engClose'
Specified export _mexFunction is not defined
Missing exports. Aborting

C:\MATLAB6P1\BIN\WIN32\MEX.PL: Error: Link of 'engwindemo.dll'
failed.


??? Error using ==> mex
Unable to complete successfully